fix(coding-agent): retry connection lost errors

closes #3317

packages/coding-agent/test/suite/regressions/3317-network-connection-lost-retry.test.ts

@@ -0,0 +1,33 @@
+import { fauxAssistantMessage } from "@mariozechner/pi-ai";
+import { afterEach, describe, expect, it } from "vitest";
+import { createHarness, getAssistantTexts, type Harness } from "../harness.js";
+
+describe("issue #3317 network connection lost retry", () => {
+	const harnesses: Harness[] = [];
+
+	afterEach(() => {
+		while (harnesses.length > 0) {
+			harnesses.pop()?.cleanup();
+		}
+	});
+
+	it('retries transient "Network connection lost." failures', async () => {
+		const harness = await createHarness({
+			settings: { retry: { enabled: true, maxRetries: 3, baseDelayMs: 1 } },
+		});
+		harnesses.push(harness);
+		harness.setResponses([
+			fauxAssistantMessage("", { stopReason: "error", errorMessage: "Network connection lost." }),
+			fauxAssistantMessage("recovered after reconnect"),
+		]);
+
+		await harness.session.prompt("test");
+
+		expect(harness.faux.state.callCount).toBe(2);
+		expect(harness.eventsOfType("auto_retry_start").map((event) => event.errorMessage)).toEqual([
+			"Network connection lost.",
+		]);
+		expect(harness.eventsOfType("auto_retry_end").map((event) => event.success)).toEqual([true]);
+		expect(getAssistantTexts(harness)).toContain("recovered after reconnect");
+	});
+});